Preheat your oven to 350°F (175°C). Grease a dome-shaped cake pan with butter or oil and dust with flour.

In a large mixing bowl, cream together the unsalted butter and granulated sugar until fluffy, about 3–5 minutes. Add eggs one at a time, then stir in vanilla extract.

In a separate bowl, mix flour, baking powder, and salt. Gradually add to the wet mixture, alternating with whole milk, until just combined.

Pour half of the batter into the pan, dollop raspberry preserves over it, and cover with the remaining batter. Use a knife to swirl.

Bake for 45–55 minutes, checking doneness with a toothpick. Cool in the pan for 10 minutes before transferring to a wire rack.

Once cooled, brush the surface with water or simple syrup and press shredded coconut onto the cake. Dust with powdered sugar if desired.